Abstract Pain and anxiety in children undergoing surgery continues to be a significant public health issue. Indeed, every year three million children who undergo surgery will suffer significant pain after surgery and high anxiety prior to surgery. Many more millions of children around the world will experience some level of surgical pain and anxiety. Although preoperative preparation for surgery has been shown to be effective in improving these outcomes in recent years most of these programs have been eliminated by hospitals;likely as a result of cost containment efforts. The surge in use of the Internet by all segments of the population has created an opportunity for a cost effective, tailored preparation program for children undergoing surgery as well as their parents. The purpose of this application is to develop, refine, and provide initial evidence for the efficacy of a data-driven web-based tailored intervention in preparation for surgery (WebTIPS). A program evaluation methodology with two consecutive phases will be employed. The first phase (Program development and refinement) will include collaboration between investigators and a well-established and acclaimed web-design company to construct the evidence-based tailored intervention. The second phase (Initial outcomes evaluation) will test the intervention on the predefined primary outcomes of anxiety and pain, providing preliminary evidence of efficacy. At the conclusion of this application, we will have preliminary data on which to base a follow-up full-scale evaluation of the efficacy and effectiveness of this program and potential moderators of its treatment effects.